High flow nasal oxygen therapy (HFNO) is an established modality in the supportive treatment of patients suffering from acute hypoxemic respiratory failure. The high humidified gas flow supports patient's work of breathing, reduces dead space ventilation, and improves functional residual capacity while using an unobtrusive patient's face interface \[Mauri et al, 2017; Möller et al, 2017\].
As hyperoxia is considered not desirable \[Barbateskovic et al, 2019\] during any oxygen therapy, the inspired O2 concentration is usually adapted to a pre-set SpO2 target-range of 92-96% in patients without hypercapnia risk, and of 88-92% if a risk of hypercapnia is present \[O'Driscoll et al, 2017; Beasley et al, 2015\]. In most institutions, the standard of care is to manually adapt the FiO2, although patients frequently have a SpO2 value outside the target range.
A new closed loop oxygen controller designed for HFNO was recently developed (Hamilton Medical, Bonaduz, Switzerland). The clinician sets SpO2 targets, and the software option adjusts FiO2 to keep SpO2 within the target ranges. The software option offers some alarms on low and high SpO2 and high FiO2. Given the capability, on the one hand, to quickly increase FiO2 in patients developing sudden and profound hypoxia, and, on the other hand, of automatically preventing hyperoxia in patients improving their oxygenation, such a system could be particularly useful in patients treated with HFNO.
A short-term (4 hours vs 4 hours) crossover study indicated that this technique improves the time spent within SpO2 pre-defined target for ICU patients receiving high-flow nasal oxygen therapy \[Roca et al, 2022\]. Due to its simplicity, HFNO is increasingly used outside the ICU during transport and in the Emergency Room (ER). This environment poses specific challenges, as patients may deteriorate very quickly and depending on patient's flow, healthcare providers can easily be overwhelmed. We thus propose to evaluate closed loop controlled HFNO in ER patients.
The hypothesis of the study is that closed loop oxygen control increases the time spent within clinically targeted SpO2 ranges and decreases the time spent outside clinical target SpO2 ranges as compared to manual oxygen control in ER patients treated with HFNO.
Patient admitted to the ER
Requiring NHFO
Requiring FiO2 ≥ 30% to keep SpO2 in the target ranges defined by the clinician
Aged over 18 years
Patient with indication for immediate CPAP, NIV, or invasive mechanical ventilation
Hemodynamic instability defined as a need of continuous infusion of epinephrine or norepinephrine > 1 mg/h
Low quality on the SpO2 measurement using finger and ear sensor (quality index below 60% on the Massimo SpO2 sensor, which is displayed by a red or orange color bar)
Severe acidosis (pH ≤ 7.30)
Crossover
Closed-loop FiO2 controller
DeviceClose-loop FiO2 controller software option provides automated adjustment of the ventilator Oxygen setting to maintain the patient's SpO2 in a defined target range. When using the software option, the user defines the SpO2 target range, as well as the SpO2 emergency limits, and the device adjusts the FiO2 setting to keep the patient's SpO2 in the target range.
Conventional
DeviceSix hours period where the fraction of inspired oxygen (FiO2) delivered will be manually titrated by clinician based on SpO2 values obtained from the patient.
Percentage of time spent in optimal SpO2 range
The optimal SpO2 range will be defined according to the SpO2 targets determined by the clinician.
Percentage of time with SpO2 signal available
Time with SpO2 signal available
Percentage of time with SpO2 below target range
SpO2 values below the optimal range
Percentage of time with SpO2 above target range
SpO2 values above the optimal range
Percentage of time with SpO2 outside optimal range
SpO2 values outside the optimal range
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Başakşehir Çam & Sakura City Hospital
Lead sponsor
Hamilton Medical AG
Collaborator
